Loss of soil quality regulation

Loss of soil quality regulation

Soil organisms, organic matter and plant cover keep soil fertile: they cycle nutrients and hold its structure. When soil quality degrades, a farm or forest has to buy fertiliser and amendments to hold its yields. Resilience books that cost as a Business interruption loss, against revenue only.

What the map shows

Soil quality regulation has no layer of its own. It is read through the natural assets ENCORE links to it:

• Today: Soils, weight 1: SOC State (2010), topsoil carbon as a share of the stock with no land use. Habitats, weight 1: Natural habitat % — baseline 2024 (LUH3), hidden from the map pickers and shown under Today. Water, weight 0.5: Water Stress (Aqueduct 4.0), by basin. Species, weight 0.5: MSA Degradation (2015).
• Projected: Soils: SOC Shock layers for SSP1-2.6, SSP2-4.5 and SSP3-7.0. Habitats: LUH3 Shock, trajectory M for SSP1 and H for SSP3. Water: Water Stress Shock, SSP1-2.6 and SSP3-7.0, by basin. Species: MSA Shock, SSP1 and SSP3. All at 2035, 2050 and 2080. Where a pathway has no layer of its own, SSP2-4.5 reads the SSP3 one.

Habitats and Species weigh 0 in subterranean ecosystems. A site spanning several biomes keeps the highest weight. At each site the service takes the most degraded supplier, after its delivery weight.

How the loss is computed

The degradation D, between 0 and 1, is the largest of (delivery weight × degradation of the natural asset) at the site. The dependency is the ENCORE rating of the site's activity, read as (rating − 1) / 4. The loss is D × min(dependency, k) × revenue, where k is the yearly cost of fertiliser and amendments, as a share of revenue. k exists for high- and low-input agriculture and managed forest. Its values are provisional placeholders. Other site types keep D × dependency. See Nature risks and Shock layers.

Sources

• Sanderman, Hengl & Fiske (2017), 0-30 cm (WHRC Soil-Carbon-Debt); CMIP6 cSoil (Emon), CESM2-WACCM, IPSL-CM6A-LR, MIROC-ES2L. Sanderman, Hengl & Fiske: MIT licence, © Woods Hole Research Center 2017. CMIP6: CC BY 4.0.
• Land-Use Harmonization 3 (LUH3), University of Maryland, CMIP7 (Zenodo / input4MIPs); HYDE 3.4 land-use reconstruction. LUH3: CC BY 4.0. HYDE 3.4: Licence not confirmed (CC BY 4.0 reported).
• WRI Aqueduct 4.0, baseline and future water-stress projections. CC BY 4.0.
• GLOBIO 4 (PBL), Schipper et al. (2020). CC BY 4.0.
• ENCORE 2024 (Global Canopy, UNEP FI, UNEP-WCMC): delivery weights and dependency ratings. CC BY-SA 4.0.

Limits

• The climate models behind the soil-carbon trend capture CO2-driven plant growth, not the carbon cultivated soils lose. The trend leans to gains.
• ENCORE also links Atmosphere (read as wind, precipitation and temperature), Land geomorphology and Minerals. None of them has a live layer, so they read no shock.
• Water stress can rise far above its baseline in relative terms. Every degradation is capped at 100 %.